Process of paper manufacture.



Pat'ented Mar. l3, I900.

F. A. FLETCHER.

PROCESS OF PAPER MANUFACTURE.

(Application filed June 26, 1899.)

(No Model.)

WITNESSES:

ATTORNEY m: uomvs were: co. nowmmu. wumNuToN. 0, c.

NTTED Sma ties FRANK A. FLETCHER, OF VATERTQWVN, NEW YORK, ASSIGNOR TOTHE AERATED PAPER COMPANY, OF NEXV YORK, N. Y.

PROCESS OF PAPER MANUFACTURE.

SPECIFICATION forming part of Letters Patent No. 645,080, dated March13, 1900.

Original application filedApril 20, 1899, Serial No. 713,699. Dividedand this application filed June 26, 1899. Serial No.

721,810. (No specimens.)

To aZZ whom it may concern.-

Be it known that I, FRANK A. FLETCHER, a

citizen of the United States, residing at Wa-' tertown, Jeffersoncounty, New York, have invented certain new and useful Improve ments inProcesses of Manufacturing Paper, of which the following is a full,clear, and exact description.

This invention relates to the manufacture of paper, and particularly toa new process therefor, this application being a division of a formerapplication serially numbered 713,699, filed April 20, 1899.

The object of this process is to obtain a product of a soft, porous, andhighly-absorbent nature.

In describing the process I will briefly allude to an apparatus (such asdescribed in detail in the referred-to original application of whichthis is a division) as illustrative of one form of apparatus by whichsuch paper may be produced. To that end, therefore, the accompanyingdrawing illustrates a vertical sectional view of a preferred form ofapparatus, parts of the same being only indicated.

The product in this process may be made from almost any kind of stockpossessing a suitable fiber, especially soda-pulp. The fiber is reducedto a pulp, and as I desire to produce a paper which is soft andextremely porous I prefer not to subject the pulp to pressure before Itreat it, as hereinafter described.

In the accompanying drawing I have shown the sheet of paper formedby acylindermachine, but do not desire to limit myself to that method offorming the sheet.

A is a vat that contains paper-pulp, a being an inlet for the same, anda an outlet for the Water from a revolving cylinder-mold B. This mold ispreferably hollow and covered with wire-cloth or other suitablematerial, and upon it is deposited the paper strip or pulp in thewell-known manner.

0 is a couch-roll, and D a roll over which and over suitableintermediate supporting or carrying rolls (1 d may pass a conveyer-beltE, preferably in the form of an endless strip of wire-cloth or othersuitable material.

The rolls 0 and D and cylindenlnold B are suitably rotated in thedirection of the arrows. The paper-pulp strip is formed upon the mold Band taken up by the wire-cloth in the manner understood in this art andcarried byit in the form of a continuous strip F of the desiredthickness.

When I speak of a strip of paper-pulp, I do not mean that the pulp mustnecessarily be made from paper, but only that it is a pulp which willform a paper, and, further, I do not mean that the paper of the stripmust necessarily be in the condition that it is when it comes from thecylinder-mold; but this latter or substantially this is preferable.

The wire-cloth belt allows some of the water in the strip to drain away,and the belt preferably passes over suction-boxes G G, which extractfrom the strip a portion of the remaining moisture. The belt may thenpass overa suitable drying means,such as heatingboxes H, located in anysuitable position and heated by anysuitable means. After leavingthe,.ro1l D the paper maypass to a conveyer K and out throughan'air-lock aperture L to rolls M, ifdesired. As the wire-cloth belt andthe strip of paper pass the heatingboxes the paper will be partiallydried. To accelerate this drying and to produce other advantageousresults, I subject the paper strip while still moist to the action of ararefied atmosphere and preferably to heat at the same time. This may beaccomplished by passing the strip through a heated chamber from whichthe air has been exhausted to any desired degree. wet or moist from thevat, I rarefyithe air within the chamber by any suitable meansforexample, the pump O- thus lowering the boiling-point of the water in thestrip, and as said strip passes the heating-boxes this water or some ofit is preferably turned into steam bubbles, which force apart theparticles of the paper strip and which, if theheat is continued, finallyevaporate, producing an ex- As the paper strip comes 1 tremely soft,porous, and highly-absorbent vert the water in the strip into steam,because if the heat is only enough to evaporate the water without firstconverting it into steam a paper will result having thesecharacteristics to a certain extent; but the paper will not be so porousas it would be if the water were converted into steam, as aforesaid. Oneimportant advantage of rarefyingthe air in the heating-chamber is thatsuch a high degree of heat is not required to convert the water in thestrip into steam or to otherwise evaporate it as would otherwise andusually be the case. This materially lessens the danger of injuring thepaper strip by a too great degree of heat, which might degrade the coloror strength of the product. In this way I can produce, if desired, acontinuous strip of soft and extreme1y-porous, consequentlyhighlyabsorbent, paper without resorting to the common expedient ofcompression. The process, therefore, mainly consists in forming a sheetof moist paper-pulp Within a substantially-closed chamber and ofrarefying and heating the air around the sheet to drive off some of themoisture therefrom.

It will be obvious that many changes may be made in the process hereindisclosed without departing from the spirit of my invention.

What I claim is- 1. The process of manufacturing paper which consists informing a sheet of moist paper in a substantially-closed space andrarefying and heating the air in said space to drive off some of themoisture from said sheet, th ereby producing a soft and porous paper.

2. The process of manufacturing paper which consists in forming a sheetof moist paper-pulp in a rarefied atmosphere and heating the same todrive off some of the moisture therefrom to substantially dry said stripwithout substantial compression, thereby producing a soft and porouspaper.

3. The process of manufacturing paper which consists in forming a stripof moist paper-pulp in a rarefied atmosphere and heating the same toassist in driving 0E the moisture from said strip, and substantiallydrying said paper without substantialcompression of the same, therebyproducing a soft and porous paper.

4. The process of manufacturing paper which consists in forming a stripof moist paper-pulp in a rarefied atmosphere, applying heat to the sameto drive off some of the moisture therefrom, and passing said sheet backand forth through said heated and rarefied atmosphere to substantiallydry said strip without substantial compression of the same, therebyproducing a soft and porous paper.

5. The process of manufacturing paper which consists in forming acontinuous strip of moist paper-pulp in a rarefied atmosphere,extracting by suction some of the moisture from said strip, applyingheat to said strip to drive off some of the moisture therefrom, andpassingsaid strip through said heated and rarefied atmosphere until thesame is substan tially dry, Without substantial compression of the same,thereby producing a soft and porous paper.

Signed at New York, N. Y., this 21st day of June, 1899. I

FRANK A. FLETCHER.

Witnesses:

EMERSON R. NEWELL, L. VREELAND.

